Southern Bracket

Ganoderma australe (frequently listed under the name G. adspersum) is one of the large, non-lacquered members of the Ganodermataceae. Unlike its varnished relatives it has a matte, often lumpy crust, but it shares the family's defining feature: double-walled, brown, truncated spores produced in such vast quantity that mature brackets are typically smothered in their own rusty-brown dust.

It is a perennial fungus. Each year a new tube layer is added beneath the previous one, so a section cut through an old specimen shows a stack of pale bands like the pages of a book, and individual brackets may reach 60 cm or more across and weigh several kilograms. That longevity, combined with a very hard upper crust, makes it one of the most durable fungal structures in temperate woodland.

The species is widespread in Europe and much of the temperate and warm-temperate world, where it is a familiar sight at the base of veteran park and street trees. Its bulk and prominence make it a landmark fungus, often persisting on the same trunk for a decade or more.

Cap

The bracket is broadly semicircular to fan-shaped, 10–60 cm wide and often 5–10 cm thick at the point of attachment. The upper surface is hard, dull and knobbly, ranging from grey-brown to deep chocolate, usually concentrically ridged and frequently coated in a layer of its own brown spores. The crust is thick — noticeably so when cut, often 1.5 mm or more — and does not dent under thumb pressure.

Pores

The pore surface is white to cream and instantly bruises dull brown where scratched, a property that gives non-lacquered Ganoderma brackets their reputation as natural drawing tablets. Pores are minute and round, around 4–6 per millimetre. In section, the tube layers are stacked in distinct annual tiers separated by thin bands of context.

Stipe

There is no stalk; the bracket is broadly sessile and attached along one edge, often growing directly out of a root buttress or a wound in the lower trunk.

Flesh & spore print

The context is dark reddish brown to chestnut, dense and woody, with few or no white mottlings. The spore deposit is a rich cocoa brown and is shed in such volume during warm weather that the upper surfaces of the bracket, the bark above, and nearby foliage are visibly coated.

Southern Bracket grows on living and dead broadleaf trees, with beech, oak, lime, horse chestnut, sycamore, poplar and fruit trees among the most frequent supports. It typically appears low on the trunk, at the root collar, or on stumps and large exposed roots, and is very common on mature trees in parks, avenues, hedgerows and old woodland.

It is widespread across Europe, especially the south and west, and occurs through Africa, Asia, Australasia and warmer parts of the Americas — the epithet australe reflects an originally southern-hemisphere description. Because the bracket is perennial, it can be found at any time of year; the visible sign of activity is the pale, actively growing white margin and the heavy brown spore fall from midsummer into autumn.

The fungus is a parasite of living heartwood that continues as a saprotroph after the tree dies, causing an intensive white rot. It degrades lignin as well as cellulose, and the decayed wood becomes pale, soft and fibrous. Because the rot is concentrated in the butt and lower trunk, colonised trees gradually lose structural stiffness at the base while the crown may still look vigorous — which is why arborists treat a large bracket at ground level as a significant sign of internal decay.

Infection normally begins through a root wound, a pruning cut or a fire scar. Colonisation is slow, sometimes proceeding for decades before the first bracket appears. The hollowing this decay produces creates roost and nest space for bats, birds and invertebrates, and the persistent woody brackets themselves are a habitat for beetles and mites.

Ganoderma applanatum, the artist's conk, is the closest match and shares the brown crust and white bruising pore surface. It differs in having a much thinner, more brittle crust that can often be dented with a thumbnail, a context that is usually paler brown with scattered whitish flecks or mounds, and a typically flatter, thinner bracket. Galls caused by a specialist midge are also common in its tubes.

Ganoderma resinaceum and the lacquered species have a glossy, varnished red-brown upper surface rather than a dull one, and are usually thinner and annual. Fomes fomentarius forms a distinctly hoof-shaped grey bracket on birch and beech with a pale brown pore surface, a fibrous brown context and a white spore deposit — never the cocoa-brown dust of a Ganoderma.